More Volumetric Analysis in ArcGIS Pro

 More Volumetric Analysis

Kendrick Wittmer

Date: 4/1/2025

    This project highlights a detailed raster analysis using UAS elevation data from a dredging operation at Litchfield Mine in Minnesota. The objective was to apply raster geoprocessing techniques to investigate volumetric changes, flooding risks, and slope stability within dynamically changing dredge piles. The analysis was based on DSMs captured on three different dates: July 4, July 22, and August 27 of 2017.

Volumetric Change Detection

    The mine operator was concerned about the accuracy of reported dredge volumes. Using elevation data clipped to a specific dredge pile and resampled to a standardized 50cm cell size, a volumetric comparison was conducted.

• July 4 Volume: 35,814.45 m³

• July 22 Volume: 58,628.39 m³

• August 27 Volume: 100,117.06 m³

The difference calculations revealed:

• 22,813.94 m³ added between July 4 and July 22

• 64,302.61 m³ added between July 4 and August 27

• 41,488.67 m³ added between July 22 and August 27

    This time-series analysis showed rapid material accumulation and was visualized across three side-by-side grayscale elevation maps with labeled volumes.

Flooding Risk Analysis

Using the August 27 dataset, flat areas where water might pool were identified using slope and aspect analysis. A raster calculator expression isolated terrain between 233–234 meters elevation, revealing specific low-lying zones likely to collect water. This spatial insight helps inform site drainage design and containment pond placement.

Slope and Stability Analysis

Multiple slope-related maps were generated to support operational safety planning:

• Slopes on Upper Reaches: Identified areas above 245 m with slope > 30°. These zones were symbolized in red atop a hillshade for elevation context.

  
  
  

• South-Facing Slopes >30°: Detected dangerous slope conditions on sun-exposed faces using aspect filtering and slope thresholding.

  
  
  

• Surface Band 233–234 m: Highlighted a narrow elevation band within the dredge pile to study potential flood lines and material flow.

  
  
  

These outputs enable better hazard awareness and support strategic pile management.

Tools & Methods Used

• Extract by Mask: Clipped dredge pile from full DSM using a polygon boundary.

• Resample: Adjusted raster resolution to 50 cm for consistency and improved performance.

• Fill: Smoothed DEM noise to allow clean slope/aspect calculation.

• Hillshade & Aspect: Created visual relief and directional slope data.

• Raster Calculator: Used for conditional logic and elevation filtering.

• Slope Analysis: Quantified steepness in critical areas using degrees.

Conclusion

    This lab demonstrated how UAS-derived raster data can inform real-world site management decisions. From identifying volumetric changes to assessing flood-prone zones and unsafe slopes, the analysis showcases the power of spatial data in active mining environments. The integration of multi-date elevation surfaces allowed for precise and actionable insights tailored to industry needs.